This competing renewal application for a NIDA Mentored Clinical Scientists Development Program Award in Drug Abuse and Addiction (K12; PAR-13-163) addresses the critical shortage of child and adolescent psychiatrists (CAPs) dually-trained in developmental psychopathology and addiction research. This is of great public health concern given ample research showing that the majority of psychiatric and substance use disorders emerge during childhood or adolescence and most often are co-occurring. According to the Institute of Medicine, this shortage has contributed to broad research gaps and a lack of effective evidence based prevention and treatment. Given their specialized training in developmental psychopathology, CAPs who go on the receive additional addiction research training may in the best position to address existing research gaps that may lead to the development of new or more effective prevention and treatment interventions for the growing number of our nation's youth who are at risk or who have developed co- occurring substance and mental health problems. Since Program inception in 1998, the NIDA/AACAP K12 Program has successfully cultivated the careers of seventeen CAP investigators. Sixteen of the seventeen have established or are well on their way to establishing careers in drug abuse and mental health research (Aim 1). Under the Program leadership of Dr. Riggs, the AACAP K12 established an ongoing partnership with the NIDA Clinical Trials Network as a training platform for AACAP K12 scholars in 2005. This partnership has significantly and meaningfully expanded the national network of senior addiction research mentors, academic research centers and training opportunities for K12 scholars (Aim 2). AACAP continues to be an ideal institutional home for the K12 given its strong institutional commitment, ample resources, and membership that includes more than 95% of CAPs in the country, including all current and previous K12 scholars. AACAP is well positioned to continue its commitment and support of scholars' career development, if the renewal is funded. Moreover, scholars' research presentations at AACAP Annual Meetings facilitate and accelerate the pace at which their research is translated into practice and impacts the field. Despite considerable Program progress towards achieving the aims of this award, the crisis-level national shortage of CAP clinicians continues. Fewer than 2% of CAPs devote significant effort to research and less than 1/2 of 1% have established careers in addiction research. This application proposes to continue building on the success of the AACAP K12 Program by addressing the following aims, which remain unchanged: Aim 1: To increase the number of independently-funded CAP addiction researchers; and Aim 2: To further expand the network of senior mentors and addiction research training centers and opportunities for K12 scholars and other early investigators.